Polarized telegraphic relay



(No Model.) 2 sne s-sheet 1. J. G. LUDWIG.

POLARIZED TELEGRAPHIG RELAY.

No. 337,272. Patented Mar. 2, 1886.

awe/whoa k N. PFrERs. Pholo-Lilho m lwr, wahington, IL C.

(No Model.) 2 Sheets-Sheet 2v J. 0. LUDWIG.

POLARIZED TBLEGRAPHIG RELAY.

No 837,272. Patented Mar. 2. 1886 PETERS, Phnlaiilboznphar, Wuhinflun.ILC.

UNITED STATES PATENT OFFICE.

JOHN G. LUDWIG, OF SAN FRANCISCO, CALIFORNIA.

POLARIZED TELEGRAPHIC RELAY.

SPECIFICATION forming part of Letters Patent No. 337,272, dated March 2,1886.

Application filed June 4, 1885. Serial No. 167,619. (No model.)

To all whom it may concern:

Be it known that I, JOHN G. LUDWIG, a citizen of the United States, anda resident of San Francisco, in the county of San Francisco and State ofCalifornia, have invented certain new and useful Improvements inTelegraphic Receiving-Instruments, of which the following is aspecification.

My invention relates to a telegraphic receiving-instrument which may beused as a mainline receiver or as a relay for opening and closing alocal circuit, including a receivinginstrument.

The special object of my present invention is to improve an instrumentshown and described in Letters Patent No. 315,427, granted to me on the7th day of April, 1885, and its general object is the same as that of mysaid previously-patented instrument-namely, to provide areceiving-instrumentwhich will respond promptly and vigorously toinduced electric currents which flow only instantly in alternatelyopposite directions, and by which this class of currents may be used fortelegraphing the Morse code of characters or signals, or other systemsin which elemental signals or characters are differentiated in respectto extent or duration.

In my present improved instrument, as in my said previously-patentedinstrument, I utilize directly but one pole of a permanent magnet, whichpole communicates a similar polarity to the two cores of anelectro-magnet, and in front of these two cores I pivot a balancedneutral armature, the opposite ends of which are attached with equalforce by the two cores when no current traverses their coils. When,however, an instantaneous current traverses the coils in one direction,one of the cores will be strengthened and the other weakened in itsattractive power. The strengthened core will then attract the adjacentend of the armature toward it, throwing the other end outward from theweakened pole. The armature being thus attracted will remain under thecontrol of the attracting core, by reason of being closer to it, until areverse current is sent through the coils. Then the operation will bereversed, and the other core will have the overpowering attraction. Itwill thus be seen that although the effect of the currents themselves isbut momentary, they may be utilized for producing movement of thearmature at any desired intervals.

My present special improvements consist in a novel construction of theneutral armature and combination thereof with the electromagnet havingcores of normally similar p0 larity,whereby the practical neutrality ofsaid armature in its normal relation to the electromagnet poles ispreserved, although its mass might become somewhat polarized by residualmagnetism resulting from the inductive influences to which it issubjected; in a novel arrangement of the permanent magnet with relationto the electro-magnet and neutral armature, whereby the unused pole ofsaid perma nent magnet is prevented from having any influence upon thearmature, and in certain novel devices for adjusting the armature withrelation to the electro-magnet poles.

My invention will be readily understood from the following particulardescription, in connection with the accompanying drawings, in whichFigure l is a side elevation of my improved telegraphicreceiving-instrument. Fig. 2 is an end view thereof. Fig. 3 is adetached view of the armature, its supports and adjusting devices. Fig.4 is a top view of the same with the supports in horizontal section.Fig.

upright position, with its poles turned downward and resting upon ahorizontal bracket, B, which is mounted upon a sliding plate orcarriage, D, havingitslongitudinal edges dovetailed into a guide-plate,0, upon which it can move lengthwise. The guide-plate is secured to abase, X. In a stationary lug, c, is arranged a horizontal screw, E,which extends under the bracket B, and has its tip in swivel connectiontherewith. It will be readily seen that by turning the screw E thesliding plate D, bracket B, and magnet A may be adjusted to differentpositions on the guide-plate.

To the outer side of one pole of the perma nent magnet A is secured theyoke-piece m of an electro-magnet, M, the coils n n of which havesoft-iron cores, to which, of course, is

' 'communicated a magnetic polarity, the same as that of the permanentmagnet-pole to which will be presently described. The plate tpro:

' jects outwardly beyond the posts T T, and in a slot in thisoutwardly-projecting portion is pivoted a depending arm, J, theintermediate portion ofwhich has a circular opening, into which extendsthe tip of a horizontal metallic arm, J, projecting from the arbor ofthe armature. Through opposite side walls of this opening; are arrangedadjustable screws j j,

' the-tips of which serve as contacts for the tip .of the arm -J. To oneside of the depending arm J is secured a spring, I, the lower portion ofwhich curves away from the arm and bears against thewall of a recessformed in the base-board, so asto force the arm J against the tip of anadjusting-screw, '1, arranged in a lug on a metallic plate, 1, uponwhich stand the posts T T. By turning the screw 1 in or out the positionof the arm J may be adjust- .ed, as when it is turned out the springwill cause the arm to'snugly follow the screw, and

the spring will yield 'to the pressure of the screw upon the arm.

The screw j has an insulated tip, while the screw j is a metalliccontactfor the tip of arm J. The metallic step-bearing t and top hearing, t, ofthe arbor'V are insulated, and the .7 arm J is connected with abinding-post, p, by

a wire, w, which passes under the base-board, while the arm J isconnected electrically with a binding-post, p, by plate t, posts T T,plate- I, and a short wire, w, passing from plate P under thebase-board'to the post. One coilterminal of the electro-magnet isconnected to a binding-post, p, and the other to a similar post, 19 Oneof the posts or p is to be connected with a line-wire, and the other tothe earth, or with a switch which may be used to connect it eitherdirectly to earth or to earth through a generator, as shown anddescribed in Letters Patent N 0. 315.425, granted to me on the 7th dayof April, 1885.

The armature R, as has been already stated, is entirely neutral so faras its operation is concerned, and it should be made of softiron. It

is arranged quite close to the poles of the elec; tro-magnet M, and whenno current traverses the coils of said magnet it will be attractedequally at both ends, and if either end is pressed closer to itsadjacent pole than the other is to the opposite pole of the magnet thearmature will remain in such position as long as no cur- 1 rent passes,and also while a current in a given direction is passing, as willbeunderstood from the further description of the operation of theinstrument.

Now, we will suppose that in the construction of the'instrument theelectro-magnet M is attached to the north pole of the permanent magnetA, and a north polarity is consequently communicated to the soft-ironcores of said electro-magnet. Suppose, further, that the induced currentgenerated and sent on the line the north polarity of core, and weaken,if not altogether neutralize, that of core of "coil n, so that the'coreof coil n will have the strongest attraction for, the armature R, andwill draw the adjacent end of said armature toward it, throwing the tipof the arm J against the contact-screw j,- a ndthus closing a localcircuit if the instrument is used as a relay. Although the magnetizingeffect of the current may cease almostlinstautly, the armature willremain attracted byjthe pole to which it is nearest until a reversecurrent passes, and by partially turning arbor V will bring the tip ofarm J against. the; screw j, and will keep the local circuit closedmeantime if the instrumentis used as a relay.; A reverse current willobviously cause the arm J to leave contact-screwy" and strike. the screwj, which is equivalent to a back-stop, andthe local circuit willbe-opened or simply a back-stroke made. In the instrument shown; anddescribed in my Patent No. 315,427 the oscillating armature is simply asolid oblong plate of soft iron, which is liable to become partiallypolarized, and in the event of such polarization the instrument losesits delicacy and becomes practically inoperative. To provide against thedeleterious effect of polarization of the armature, Ihave formed it ofalong thin strip,

with itsend portions bent back, as shown at r r, Fig. 5, and approachedclose to each other, without touching behind the intermediate portion,r, which stands between thetips and the magnet. Now, if such a stripbecomes polarized, its poles will be at its tips and away from themagnetcores, which will face the intermediate and neutral portion, r.The polarization of the armature, therefore, shouldit occur, will havepractically no effect so far as its neutral relation to the magnet-coresis concerned, and especially as the intermediate portion forms ametallic screen to intercept any inductive influence of thearmature-poles toward the magnet-cores.

In my former patent the permanent magnet was arranged with both itspoles toward the,

armature, and was not adjustable. The unused pole in that form is sonear to the armature that it may have some inductive influence thereuponand interfere withits action to such an extent as to prevent it fromresponding promptly to reversals of current if the current be weak, asit may be on long lines.

In my present improvement I have taken care to remove the unused pole tothe greatest practicable distance from the armature, and have arrangedit behind the utilized pole, so that the latter acts to intercept theinductive influence of the said unused pole, and prevent any deleteriousinfluence of the sameupon the armature,

In my former patented instrumentI did not provide means for regulatingthe distance between the armature and the magnet-cores. Such means havebeen supplied in my present improvement by mounting the permanent magnetupon the adjustable sliding plate, and while the pendent arm J, its adjusting-screw I, and the adj ustable screws 9' j serve to bring thearmature to an exact magnetic balance with respect to the magnet cores,the said screws j and j are for the special purpose of regulating theamplitude of the oscillations of the armature, so that neither end ofthe same' can ever swing outward beyond the eflicient field of therespective magnet-cores.

I prefer to make the armature of soft sheetiron, commonly known asRussia iron, though of course other iron, either cast or wrought, mightbe used. Thearm J may be connected with the binding-post p by anysuitable means which will not interfere with its vibration,

Having now described my invention and explained the operation thereof, Iclaim- 1. In a telegraphic receivinginstrument of the class described,the combination, with the electro-magnet having cores of normallysimilar polarity, of the oscillating armature having its end portionsbent back away from the magnet-cores, essentially as and for the purposeset forth.

2. The neutral armature formed of a softiron strip bent back at bothends, as described 3. In a telegraphic receiving-instrument of the kinddescribed, the combination, with the neutral oscillating armature andelectro-mag net, of the permanent magnet having one end attached to theyoke-piece of said electro-magnet, and its other end arranged behindsaid attached end and on the opposite side thereof from the neutralarmature, substantially as and for the purpose set forth.

4. The combination, with the electro-magnet and its oscillating neutralarmature mounted upon a vertical arbor, of the arm J, projecting fromsaid arbor, the pendent pivoted adjustable arm J, and the adjustablestops upon said arm, substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signed myname, in presence of two witnesses, this 25th day of May, 1885.

JOHN C. LU DWIG,

\Vitnesses:

GEO, T. KNOX, H. LANG.

